An insulator housing comprises a hollow insulator body of an insulating material, for example, porcelain or a polymer composite, and at least one end of the insulator body is an metallic flange of, for example, steel or aluminium attached. The metallic flange can be attached to the hollow insulator body in different ways, for example, press fitting, crimping, gluing or cementing.
An insulator housing is used in a variety of electrical products for high voltage, for example, surge arresters, breakers or bushings.
The insulator housing is usually attached to an external device through the flange that is attached to at least one end of the insulator. The external device is, for example, an arrester base structure when the insulator housing is part of a surge arrester, a second insulator housing, or a transformer housing when the insulator housing is part of a bushing for a transformer. Depending on the design of the insulator housing and the load the insulator housing shall withstand, the number of bolts/fixing points to the external device can vary. FIG. 1 shows an example of an insulator housing according to prior art, being attached to an external device.
Sometimes the part of the flange where the flange is attached to the external device, such as second insulator housing or a base structure, is weakened during use due to mechanical overloading or cracks, such as frost cracks. It might then be the case that the flange will not be able to withstand the initially specified mechanical loads given by the manufacturer. This could be overcome by disassembly of the equipment comprising the insulator and exchange of the insulator housing with a damaged flange to a new insulator housing with undamaged flanges. However, this will be complicated, expensive and time consuming. It is therefore a need to find an alternative way to strengthen the insulator housing.